An experienced criminal defense lawyer may be able to help you get this dismissed. Diversion programs are oftentimes available for first time shoplifters. I'd have to know more facts to determine if you'd be eligible. No, talking to the manager won't do you any good whatsoever. Hire a lawyer ASAP.
If you don't have any prior criminal history, an attorney can probably help you get into a pre-trial diversion program. I'm not sure which jurisdiction you are in (assuming Clayton County), but Clayton County does have a pre-trial diversion program: http://www.claytoncountyga.gov/courts/solicitor-general/initiatives/pre-trial-intervention-diversion.aspx. In a nutshell, the program would require you to pay a certain amount of money, take a class, and do some community service, although the terms of the program can differ depending on the case and jurisdiction. If you successfully complete the program, the charge will be dismissed. Contact an attorney to help you get into the program. I have handled several shoplifting cases, so please contact me at 706-614-5631 if I can be of any help.
As a general rule you should never speak to anyone about these charges except an attorney. Hire a lawyer to advise you of your options and leave any deal-making to him or her. A statement like that to Wal-Mart would likely be considered an admission of guilt and could be used against you. Once you hire a lawyer, he or she should advise you about any diversion programs which may be available in your jurisdiction for first-time offenders.